MeeGo is a Linux-based operating system designed by Intel and Nokia for netbooks and smart phones. Installing MeeGo on an Eee PC 1000 netbook is quick slick and easy. I found the user interface to be colourful and stylish with many quirky animations. MeeGo's features are easy to discover and it is fast and responsive.

the last partition is a 50MB partition that the Eeepc BIOS uses to store some data to abreviate the POST of your netbook.
I whole-heartedly recommend keeping the fourth partition whatever you do. Those 50 megabytes saves about ~7 seconds of boot time. Provided you're using the HDD that comes with your 1000he, all that needs to be done in order to keep the quick post working after you wipe is to leave partition 4 alone.
If you delete the EFI partition by mistake, you can restore Boot Booster by creating a 50MB primary partition at the end of your hard drive. Label it as EFI (0xef) from within fdisk. The contents of the partition are not important as it is only a caching area for the BIOS.

I am pretty certain that the partition must be FAT formatted. It's a rule for EFI. I have no idea how the BIOS would manage to write data into an unformatted partition in any standard manner. If they did it would make nonsense of the EFI partition type.